drop if (exporter=="TKY" | importer=="TKY")
drop if (exporter=="JAM" | importer=="JAM")
drop if (exporter=="SYR" | importer=="SYR")
drop if (exporter=="NOR" | importer=="NOR")
drop if (exporter=="INO" | importer=="INO")
drop if (exporter=="SPN" | importer=="SPN")
drop if (exporter=="ARG" | importer=="ARG")
drop if (exporter=="SUD" | importer=="SUD")
drop if (exporter=="DEN" | importer=="DEN")
drop if (exporter=="GUA" | importer=="GUA")
drop if (exporter=="US" | importer=="US")
drop if (exporter=="MAW" | importer=="MAW")
drop if (exporter=="PHI" | importer=="PHI")
drop if (exporter=="THA" | importer=="THA")
drop if (exporter=="CAN" | importer=="CAN")
drop if (exporter=="NET" | importer=="NET")
drop if (exporter=="CHN" | importer=="CHN")
drop if (exporter=="SWE" | importer=="SWE")
drop if (exporter=="EGT" | importer=="EGT")
drop if (exporter=="UK" | importer=="UK")
drop if (exporter=="NEZ" | importer=="NEZ")
drop if (exporter=="ECU" | importer=="ECU")
